Issue #3414173 by joelpittet, anybody, nicxvan: Add support for minified external CSS libraries

        $data .= "/* @license " . $css_asset['license']['name'] . " " . $css_asset['license']['url'] . " */\n";

      }

      $current_license = $css_asset['license'];

      // Append this file if already minified; otherwise optimize it.

      if (isset($css_asset['minified']) && $css_asset['minified']) {

        $data .= file_get_contents($css_asset['data']);

      }

      else {

        $data .= $this->optimizer->optimize($css_asset);

      }

    }

    // Per the W3C specification at

    // https://www.w3.org/TR/REC-CSS2/cascade.html#at-import, @import rules must

    // precede any other style, so we move those to the top. The regular

    self::assertStringEqualsFile(__DIR__ . '/css_test_files/css_license.css.optimized.aggregated.css', $aggregate);

  }

  /**

   * Test that external minified CSS assets do not trigger optimization.

   *

   * This ensures that fully external asset groups do not result in a

   * CssOptimizer exception and are safely ignored.

   */

  public function testExternalMinifiedCssAssetOptimizationIsSkipped(): void {

    $mock_grouper = $this->createMock(AssetCollectionGrouperInterface::class);

    $mock_optimizer = $this->createMock(AssetOptimizerInterface::class);

    $mock_optimizer->expects($this->never())->method('optimize');

    $optimizer = new CssCollectionOptimizerLazy(

      $mock_grouper,

      $mock_optimizer,

      $this->createMock(ThemeManagerInterface::class),

      $this->createMock(LibraryDependencyResolverInterface::class),

      new RequestStack(),

      $this->createMock(FileSystemInterface::class),

      $this->createMock(ConfigFactoryInterface::class),

      $this->createMock(FileUrlGeneratorInterface::class),

      $this->createMock(TimeInterface::class),

      $this->createMock(LanguageManagerInterface::class)

    );

    $optimizer->optimizeGroup([

      'items' => [

        [

          'type' => 'external',

          'data' => __DIR__ . '/css_test_files/css_external.optimized.aggregated.css',

          'license' => FALSE,

          'preprocess' => TRUE,

          'minified' => TRUE,

        ],

      ],

    ]);

  }

}

/* Placeholder external CSS file. */